Fertilizing Clematis: High Phosphorus (10-20-10), Three Times a Year

Clematis Need Phosphorus for Flowers, Not Nitrogen for Leaves

• Use 10-20-10 or rose food (high middle number = phosphorus).
• Apply 3×/year: April, June, August.
• If actively growing in March, start then. Don't feed dormant plants.

Bonus: Grape Fertilizing

• Balanced 10-10-10 or 12-12-12.
• Or composted manure.
• Missouri Extension Grape Guide.

High nitrogen = jungle vines, few flowers. Phosphorus = blooms.